KR20120020071A - Exhaust gas cleaning system for engineering vehicle - Google Patents

Abstract

PURPOSE: A system for purifying exhaust gas of a working vehicle is provided to avoid unnecessary temperature increase assist and prevent a worsening of operability when work is resumed. CONSTITUTION: A system for purifying exhaust gas of a working vehicle comprises a diesel engine(1), a driven unit, an operating unit, a stopping unit, a filtering unit, a play device, a play control device, and a temperature increase assist unit. The play device increases the temperature of exhaust gas and removes particulate materials from a filter. The play control device controls the start and stop of the operation of the play device. The temperature increase assist unit assists the temperature increase of the play device. The play control device starts the operation of the temperature increase assist unit when the stopping unit operates to stop the operation of the driven unit during operation of the play device.

Description

Exhaust gas purification system of work vehicle {EXHAUST GAS CLEANING SYSTEM FOR ENGINEERING VEHICLE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purification system for a work vehicle. In particular, the filter collects particulate matter contained in the exhaust gas to purify the exhaust gas, and incinerates and removes the particulate matter collected in the filter appropriately. An exhaust gas purification system for a work vehicle to be regenerated.

Work vehicles such as hydraulic excavators are equipped with a diesel engine as a driving source, but the emissions of particulate matter (PM: particulate matter: PM) discharged from the diesel engine are generated every year together with NOx, CO, HC, and the like. Regulation is tightening. In response to such regulation, an exhaust gas purification system is known in which PM is collected by a filter called a diesel particulate filter (DPF) to reduce the amount of PM discharged to the outside. In this exhaust gas purification system, if the amount of PM replenishment of the filter is increased, the filter may be clogged, thereby increasing the back pressure of the engine and causing deterioration of fuel efficiency. Therefore, the PM collected in the filter is properly burned to block the filter. Remove the filter to play the filter.

Regeneration of the filter is usually performed by using an oxidation catalyst. The oxidation catalyst may be disposed upstream of the filter, directly supported on the filter, or both. However, in any case, the temperature of the exhaust gas must be higher than the active temperature of the oxidation catalyst to activate the oxidation catalyst. However, there is a technique called forced regeneration in which the exhaust gas temperature is forcibly raised above a set temperature (threshold value) suitable for regeneration, which is higher than the active temperature of the oxidation catalyst. In this forced regeneration, a method of heating the exhaust gas by performing partial injection (post-injection) for injecting fuel in the expansion stroke after the main injection of the engine cylinder and exhaust gas flowing through the exhaust pipe by the regeneration fuel injection device installed in the exhaust pipe And the like to inject fuel to heat up the exhaust gas.

The forced regeneration of the filter includes manual regeneration to start regeneration by an operator's operation input and automatic regeneration to automatically start regeneration. Manual reproduction is performed as follows. First, the PM accumulation amount (accumulation amount) of the filter is estimated, and when the PM accumulation amount reaches a preset PM accumulation limit value, the operator is warned to perform manual regeneration. When the operator operates the manual regeneration switch, regeneration is started. Patent document 1 discloses a technique relating to passive regeneration. On the other hand, automatic regeneration is performed when the PM accumulation amount reaches an accumulation limit value or when a predetermined time set in advance has elapsed. Patent document 2 discloses a technique relating to automatic regeneration. In both manual regeneration and automatic regeneration, the PM accumulation amount is generally determined by detecting the differential pressure before and after the filter and calculating based on the detected value of the differential pressure.

By the way, the engine output and the exhaust gas temperature are closely related, and when the engine output is lowered, the exhaust gas temperature is also lowered. When the exhaust gas temperature itself is low, even if forced regeneration is performed, there is a possibility that the temperature cannot be sufficiently raised, so that a good regeneration is not performed. With respect to such a problem, Patent Document 3 proposes an exhaust gas purification system to which a temperature raising assist means is added.

The exhaust gas purification system is provided with a neutral detection device of the operation lever, and starts the temperature assist assist when the neutral position is detected, and stops the temperature assist assist when the operation position switched from the neutral position is detected. This temperature raising assist means raises exhaust gas temperature by adjusting the discharge pressure and discharge flow volume of a hydraulic pump, and raising an engine output.

International Publication No. WO2009 / 060719 Japanese Patent Application Publication No. 2009-79500 Japanese Patent Application Laid-open No. Hei 7-166840

As described above, the exhaust gas purification system according to the prior art has started the temperature raising assist based on the neutral position of the operation lever, and has the following problems (first).

For example, in the hydraulic excavator, when the work by the front work machine is performed through the operation lever, the engine output increases and the exhaust gas temperature also increases. On the other hand, when the operation lever is made neutral, the engine output is lowered, but the exhaust gas temperature is not immediately lowered. The exhaust gas temperature gradually decreases, but when the operation is resumed by operating the operation lever again, the engine output increases and the exhaust gas temperature also rises again. In other words, even if the operation lever is made neutral during the work, it is not always necessary to perform the temperature raising assist.

Unnecessarily raising the temperature may cause the melt of the filter due to abnormal rise. Moreover, it is not preferable also from a viewpoint of energy saving.

Moreover, the exhaust gas purification system which concerns on the prior art has stopped the temperature raising assist based on the operation position of an operation lever, and had the following (second) problems.

Normally, when the operation lever is set to neutral, the engine is idle, and the engine output PSmin (pump discharge pressure P1 and pump discharge flow rate Q1) is set from the viewpoint of energy saving. If it is set to neutral, the engine output PSmax (pump discharge pressure P2 (> P1) / pump discharge flow rate Q2) (> Q1) is set for temperature assist. And when switching an operation lever from a neutral position to an operation position, it adjusts so that it may become a pump discharge pressure P1 and pump discharge flow volume Q1, and it may become an engine output PSmin. As a result, the temperature raising assist is stopped.

At this time, the discharge pressure of the pump is adjusted by the switching control of the pressure control valve, and the discharge flow rate of the pump is adjusted by the tilting control of the regulator. After the control command is input, a response time occurs until the pressure control valve or regulator is activated. That is, even if the control command is made so as to be P2? P1, Q2? Q1, it does not immediately become P1, Q1, but the discharge pressure higher than P1 and the discharge flow rate higher than Q1 are maintained for a certain time.

In a state in which the temperature assist assist is not completely stopped, when the fine operation operation is to be performed through the operation lever, the front work machine may be driven more than the operator intends, and the operability is impaired. In addition, when the work is performed by the front work machine, an excessively excessive load is applied to the engine, a sudden drop in engine speed (lag down) occurs, and the operability is significantly impaired.

Thus, the exhaust gas purification system which concerns on the prior art had the problem (1) regarding unnecessary temperature raising assist, and the problem (2) regarding deterioration of operability at the time of work resumption.

An object of the present invention is to provide an exhaust gas purification system that can avoid unnecessary temperature rising assist and at the same time prevent deterioration of operability at the time of restarting work.

(1) In order to achieve the above object, the present invention provides a diesel engine, a driven body driven by the power of the engine, operation means for instructing the operation of the driven body, and an operation of stopping the operation of the driven body. A filter device which is provided in a work vehicle having a stop means and is disposed in the exhaust system of the engine and includes a filter for collecting particulate matter contained in the exhaust gas, and the temperature of the exhaust gas is raised to be deposited on the filter. An exhaust gas purification system for a work vehicle, comprising: a regeneration device for incineration and removal of particulate matter; And the regeneration control device is further configured to stop the operation of the driven member during operation of the reproducing device. As the support means is operated, thereby starting the operation of said temperature raising assist means.

When the operation stop means is operated to stop the operation of the driven member, the time during which the engine output is lowered becomes longer. When the engine output is lowered, the exhaust gas temperature is also gradually lowered, which is likely to be below the threshold value (set temperature suitable for regeneration). In other words, by starting the temperature assist only when necessary, unnecessary temperature assist can be avoided.

(2) In the above (1), preferably, further comprising an exhaust temperature detecting device for detecting the temperature of the exhaust gas, wherein the regeneration control device stops the operation of the driven member during operation of the regenerating device. The operation stop means is operated so that the operation of the temperature increasing assist means is initiated when the exhaust temperature detection device detects a temperature below a threshold value.

In this manner, by starting the temperature raising assist only when the exhaust gas temperature is less than the threshold value, unnecessary temperature raising assist can be further avoided.

(3) In the above (1), preferably, the regeneration control device stops the operation of the temperature increasing assist means when the operation stop means is operated to release the operation stop of the driven member.

After the operator operates the operation stop means to release the operation stop of the driven body to operate the driven body, some time occurs until the operation means is operated to drive the driven body to resume work. This time is longer than the response time from the temperature assist stop command until the operation of the assist means stops, and the operation of the assist means is reliably stopped when the work is resumed. Thereby, deterioration of operability at the time of resuming work can be prevented.

(4) In the above (1), preferably, the work vehicle has a hydraulic pump driven by the engine, and the temperature raising assist means adjusts at least one of the discharge pressure and the discharge flow rate of the hydraulic pump. Apply hydraulic load to the engine.

(5) In the above (1), preferably, the work vehicle includes an engine control device for controlling the engine, and the temperature raising assist means adjusts the rotational speed of the engine during the operation of the regeneration device. The engine control device is instructed to have a higher predetermined rotation speed.

(4) By the structure of (5), engine output rises and a temperature rising assist means can assist the temperature rising of the exhaust gas at the time of regeneration.

(6) In the above (1), preferably, the operation stop means is a gate selectively operated at a first position enabling the operation of the driven member and a second position at which the operation of the driven member is disabled. It is a lock lever.

(7) In the above (1), preferably, the operation stop means is a parking brake that is operated to brake running when the working vehicle is parked.

(8) In the above (1), preferably, the operation stop means is a shift lever which is selectively switched to a forward position, a neutral position and a reverse position.

By operating operation stop means such as a gate lock lever, a parking brake, a shift lever, and the like, the operation of the driven body (for example, a front work machine or a traveling system) can be stopped.

According to the present invention, unnecessary heating assist can be avoided, and deterioration of operability at the time of restarting work can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows the whole structure of exhaust gas purification system (1st Embodiment).
2 is a view showing a hydraulic drive device mounted on a hydraulic excavator.
3 is a view showing an appearance of a hydraulic excavator.
4 shows a functional block of a controller.
5 is a flowchart showing the processing contents of the temperature assist assist control;
Fig. 6 is a diagram showing the relationship between the discharge pressure and the discharge flow rate of the hydraulic pump and the output of the engine.
FIG. 7 is a diagram illustrating an example of the passage of time of the exhaust gas temperature. FIG.
8 is a diagram illustrating an overall configuration of an exhaust gas purification system (modified example).
9 is a view showing an appearance of a wheel loader (third embodiment).
10 illustrates a functional block of a controller.
11 is a flowchart showing the processing contents of the temperature assist assist control;
12 is a flowchart showing processing contents of a temperature increase assist control;

<1st embodiment>

... composition ...

EMBODIMENT OF THE INVENTION Hereinafter, 1st Embodiment of this invention is described using drawing.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the whole structure of the exhaust gas purification system of the work vehicle which concerns on this embodiment of this invention. In FIG. 1, the working vehicle (for example, a hydraulic excavator) is equipped with the diesel engine 1, and this engine 1 is equipped with the electronic governor 1a which is an electronic fuel injection control apparatus. The target rotational speed of the engine 1 is commanded by the engine control dial 2, and the actual rotational speed of the engine 1 is detected by the rotational speed detection device 3. The command signal of the engine control dial 2 and the detection signal of the rotation speed detection device 3 are input to the controller 4, and the controller 4 receives the command signal (target rotation speed) and the detection signal (real rotation speed). The electronic governor 1a is controlled based on the control, and the rotation speed and torque of the engine 1 are controlled.

The gate lock lever 5 is provided in the hydraulic excavator at the left front side of the driver's seat 108. The gate lock lever 5 can be selectively operated in a first position A, which is a lowered position that restricts the entrance of the driver's seat 108, and in a second position B, which is an raised position for opening the entrance of the driver's 108. .

The exhaust gas purification system is disposed in the exhaust pipe 31 constituting the exhaust system of the engine 1, and filters the particulate matter contained in the exhaust gas and an oxidation catalyst disposed upstream of the filter 32 ( DPF apparatus 34 including 33), position detecting apparatus 35 for detecting the operation position of gate lock lever 5, and forward and backward differential pressures of filter 32 upstream and downstream (filter 32 Pressure loss] 36, an exhaust temperature detecting device 37 provided upstream of the filter, detecting the temperature of the exhaust gas, a regeneration switch 38 for instructing manual regeneration, And a regeneration fuel injection device 39 provided between the engine 1 of the exhaust pipe 31 and the DPF device 34 to raise the temperature of the exhaust gas. The oxidation catalyst 33 and the regeneration fuel injection device 39 incinerate and remove PM (particulate matter) deposited on the filter 32 to form a regeneration device for regenerating the filter 32.

2 is a view showing a hydraulic drive device mounted on a work vehicle (for example, a hydraulic excavator). The hydraulic drive device includes a main hydraulic pump 11 of a variable displacement type and a fixed displacement pilot pump 12 driven by an engine 1, and a hydraulic motor driven by pressure oil discharged from the hydraulic pump 11. A plurality of hydraulic actuators including the 13 and the hydraulic cylinders 14 and 15, and the flow of the hydraulic oil supplied from the hydraulic pump 11 to the hydraulic motor 13 and the hydraulic cylinders 14 and 15 (flow rate and direction) A plurality of flow control valves including pilot operated flow control valves 17 to 19 to control the pressure and pressure of the pressure oil discharged from the pilot pump 12 are kept constant to form a pilot hydraulic pressure source 20. Downstream of the center bypass line connecting the pilot relief valve 21, the main relief valve 22 defining the upper limit of the discharge pressure of the main hydraulic pump 11, and the flow control valves 17 to 19 in series. The control valve 30 and the pilot hydraulic power source 20 installed on the side An electromagnetic switching valve 23 connected to the downstream side and controlled ON / OFF according to the opening / closing condition of the gate lock lever 5 provided at the driver's seat inlet of the hydraulic excavator, and a pilot flow path downstream of the electromagnetic switching valve 23 ( Remote controller valves 25, 26, 27 connected to 24 to generate control pilot pressures a to f for operating the flow control valves 17 to 19 using the hydraulic pressure of the pilot hydraulic source 20 as the original pressure. ).

The remote controller valves 25, 26, 27 are operated by left and right operation levers 28, 29 provided on the left and right sides of the driver's seat 108. The operation levers 28 and 29 can be operated in the crosswise direction, respectively, and when the operation lever 28 is operated in one direction of the cross, the remote controller valve 25 is operated, and the operation lever 28 is crosswise. Direction, the remote controller valve 27 is operated. When the operation lever 29 is operated in one direction of the cross, the remote controller valve 26 is operated, and the operation lever 29 is operated in the other direction of the cross. The remote controller valve is not operated. Further, when operating the operation lever 28 in one direction of the cross, when operating in one direction from the neutral position, the remote controller valve 25 generates the control pilot pressure a, and when operating in the opposite direction from the neutral position, the remote controller valve ( 25) generates the control pilot pressure b. Control pilot pressures a and b are led to the corresponding hydraulic parts of the flow control valve 17 via respective pilot lines 25a and 25b, whereby the flow control valve 17 is switched from the neutral position.

Similarly, when operating the operation lever 28 in the other direction of the cross, when operating in one direction from the neutral position, the remote controller valve 27 generates the control pilot pressure e, and when operating in the opposite direction from the neutral position, the remote controller valve 27 generates the control pilot pressure f, and the control pilot pressures e, f are led to the corresponding hydraulic parts of the flow control valve 19 through the respective pilot lines 27a, 27b, whereby the flow control valve ( 19) is switched from the neutral position. When operating the operation lever 29 in one direction of the cross, operating in one direction from the neutral position produces the control pilot pressure c, and operating in the opposite direction from the neutral position generates the control pilot pressure d, and the control pilot pressure c, d is led through the respective pilot lines 26a and 26b to the corresponding hydraulic pressure portion of the flow control valve 18, thereby switching the flow control valve 18 from the neutral position.

The control pilot pressures a to f communicate and cut off based on the position of the gate lock lever 5.

When the gate lock lever 5 is in the first position A, the solenoid of the electromagnetic switching valve 23 is excited to switch the electromagnetic switching valve 23 from the position shown, and the pressure of the pilot hydraulic source 20 is reduced. It guides to the remote controller valves 25, 26, 27, thereby enabling the operation of the flow control valves 17-19 by the remote controller valves 25, 26, 27. When the gate lock lever 5 is raised to the second position B, the solenoid of the electromagnetic switching valve 23 is released to switch the electromagnetic switching valve 23 to the position shown, and the pilot hydraulic source 20 ) And the communication between the remote controller valves 25, 26, 27 are blocked, thereby disabling operation of the flow control valves 17-19 by the remote controller valves 25, 26, 27. That is, when the gate lock lever 5 is operated to raise to the 2nd position B, it will be in the lock-on state with respect to the remote controller valve 25, 26, 27 (control lever unit). When the gate lock lever 5 is lowered to the first position A again, the lock state is released. The switching of the position of the electromagnetic switching valve 23 by the gate lock lever 5 is, for example, by providing a switch (not shown) between the solenoid of the electromagnetic switching valve 23 and the power supply, so that the gate lock lever 5 When in the first position A, turn the switch ON (closed) to excite the solenoid. When the gate lock lever 5 is operated to the second position B, turn the switch OFF (open) to Do it by releasing the woman.

The control valve 30 is a two-position switching valve having an open position and a closed position. When the solenoid is not excited, the control valve 30 is in an open position. When the solenoid is excited, the control valve 30 is switched from the shown open position to the closed position.

3 is a view showing an appearance of a hydraulic excavator. The hydraulic excavator is provided with a lower traveling body 100, an upper swinging body 101, and a front work machine 102. The lower traveling body 100 has left and right crawler type traveling devices 103a and 103b and is driven by the left and right traveling motors 104a and 104b. The upper revolving body 101 is pivotally mounted on the lower traveling body 100 by the revolving motor 105, and the front work machine 102 is provided to be able to float on the front portion of the upper revolving body 101. . The upper swinging structure 101 is provided with an engine room 106 and a cab 107, an engine 1 is arranged in the engine room 106, and a gate lock lever is provided at the entrance of the driver's seat 108 in the cab 107. (5) (FIG. 1) is provided, and the control lever unit (not shown) which has the built-in remote controller valve 25, 26, 27 in the driver's seat 108 is arrange | positioned.

The front work machine 102 is a multi-joint structure having a boom 111, an arm 112, and a bucket 113, and the boom 111 rotates up and down by the expansion and contraction of the boom cylinder 114, and the arm 112. ) Rotates up and down and front and rear directions by the expansion and contraction of the arm cylinder 115, and the bucket 113 rotates up and down, front and rear directions by the expansion and contraction of the bucket cylinder 116.

In FIG. 2, the hydraulic motor 13 corresponds to, for example, the turning motor 105, the hydraulic cylinder 14 corresponds to, for example, the arm cylinder 115, and the hydraulic cylinder 15, For example, it corresponds to the boom cylinder 114. Although the hydraulic drive apparatus shown in FIG. 2 is also equipped with the other hydraulic actuators and control valves corresponding to the traveling motors 104a and 104b, the bucket cylinder 116, etc., illustration is abbreviate | omitted in FIG.

~ Control ~

4 is a diagram illustrating the functional blocks of the controller 4. The controller 4 includes a body controller 41 and an engine controller 43, which are connected to each other via a communication line 44 to form a vehicle body network. The command signal of the engine control dial 2, the detection signal of the position detection device 35, the differential pressure detection device 36, and the exhaust temperature detection device 37 are input to the vehicle body controller 41, and the rotation speed detection device 3. ) Is input to the engine controller 43.

The engine controller 43 receives a command signal of the engine control dial 2 via the communication line 44, and based on the command signal and the detection signal of the rotation speed detection device 3, the engine speed of the engine 1 is reduced. And torque control.

The vehicle body controller 41 controls the entire vehicle body such as a hydraulic drive device. For example, by controlling the regulator of the control valve 30 and the hydraulic pump 11, the discharge pressure and discharge flow volume of the hydraulic pump 11 are controlled. The regeneration control and the temperature assist assist control are one function of the vehicle body controller 41.

The vehicle body controller 41 receives the detection signal of the differential pressure detecting device 36, estimates the PM deposition amount, performs arithmetic processing of the regeneration control based on the estimated PM deposition amount, and transmits a control signal according to the operation result to the communication line. Transmission to the engine controller 43 via the 44, and the engine controller 43 controls the electronic governor 1a and the regeneration fuel injection device 39 according to the control signal (automatic regeneration control). In addition, the vehicle body controller 41 receives the command signal of the regeneration switch 38 and performs arithmetic processing of regeneration control (manual regeneration control).

The rise assist control of the vehicle body controller 41 will be described. The vehicle body controller 41 receives the detection signals of the position detection device 35 and the exhaust temperature detection device 37, performs calculation processing of the temperature assist assist control based on these detection signals, and generates a control signal according to the calculation result. Output to the regulator of the control valve 30 or the hydraulic pump 11, and controls the discharge pressure and discharge flow volume of the hydraulic pump 11. As shown in FIG. Thereby, the load of the engine 1 which drives the hydraulic pump 11 increases, and the exhaust gas temperature of the engine 1 rises.

5 is a flowchart showing the processing contents of the temperature assist assist control of the vehicle body controller 41.

The vehicle body controller 41 first determines whether the vehicle body controller 41 itself is performing reproduction control (step S10), and determines that the vehicle body controller 41 is performing reproduction control, based on the detection signal of the position detection device 35, It is determined whether the gate lock lever 5 has been raised to the second position B, that is, whether or not the gate lock lever 5 is in the lock-on state for blocking the control pilot pressure (step S20). If it is determined that (5) is in the lock-on state, it is judged based on the detection signal of the exhaust temperature detecting device 37 whether or not the exhaust gas temperature is lower than a threshold (set value suitable for regeneration) (step S30). If it is determined that the exhaust gas temperature is less than the threshold value, the discharge pressure and the discharge flow rate of the hydraulic pump 11 are controlled, and a hydraulic load is applied to the engine 1 to start the temperature assist (step S40).

When it is determined in step S10 that the regeneration control is not performed, when it is determined in step S20 that the gate lock lever 5 is not in the lock-on state (in the first position A), in step S30 In the case where it is determined that the exhaust gas temperature is not lower than the threshold (it is at a temperature suitable for regeneration), the procedure returns to the procedure immediately after the start, and the procedures of steps S10 to S30 are repeated.

The temperature rising assist start in step S40 is performed as follows, for example. 6 is a diagram illustrating a relationship between the discharge pressure and the discharge flow rate of the hydraulic pump 11 and the output of the engine 1. Normally, when the gate lock lever 5 is in the lock-on state and no work is performed, it is controlled by the pump discharge pressure P1 and the pump discharge flow rate Q1 from the viewpoint of energy saving, and the minimum engine output ( PS1). When the temperature assist assist command is output, the pump discharge pressure P2 (> P1) and pump discharge flow rate Q2 (> Q1) are controlled, and the engine 1 drives the engine output PS2 to drive the hydraulic pump 11. ), The load of the engine 1 increases, and the exhaust gas temperature of the engine 1 increases.

After the temperature assist start, which of the judgment (condition 1) in step S10, the judgment in step S20 (condition 2), and the judgment in step S30 (condition 3) is no (any of conditions 1 to 3) It is determined whether or not one is satisfied (step S50), and if either is determined to be no, the temperature raising assist is stopped (step S60).

The temperature assist assist stop in step S60 is controlled by the pump discharge pressure P1 and the pump discharge flow rate Q1, and it is carried out by making it the minimum engine output PS1. The load on the engine 1 is reduced, and the exhaust gas temperature of the engine 1 drops.

In the case where it is determined in step S50 that all are not NO (satisfying all of the conditions 1 to 3), the procedure of step S50 is repeated to continue the temperature assist.

~ Action ~

The operation of the exhaust gas purification system of the first embodiment will be described. 7 is an example of the time course of the exhaust gas temperature, shown for assistance in understanding.

At the end of the work by the work vehicle (hydraulic shovel), the operator raises the gate lock lever 5 from the first position A to the second position B to bring it into the locked on state. At this time, if the PM accumulation amount reaches the accumulation limit value, automatic regeneration is started. In addition, since automatic regeneration is started during the operation, the operator may interrupt the operation and place the gate lock lever 5 in the locked on state.

In general, immediately after the end of the operation or during the operation, the exhaust gas temperature is higher than the activation temperature of the oxidation catalyst 33, and the fuel is injected into the exhaust pipe 31 by controlling the regeneration fuel injection device 39. (unburnt fuel) is supplied to the oxidation catalyst 33, the unburned fuel is oxidized by the oxidation catalyst 33, and the exhaust gas temperature further rises by the reaction heat obtained at that time, and PM accumulated in the filter 32 This incineration is removed.

At this time, since the exhaust gas temperature detected by the exhaust temperature detecting device 37 is equal to or greater than the threshold value, the temperature raising assist is not performed (step S10? S20? S30? S10) (FIG. 7 state 1).

Normally, when the gate lock lever 5 is in the locked on state and no work is performed, the minimum engine output PS1 is controlled by the pump discharge pressure P1 and the pump discharge flow rate Q1 from the viewpoint of energy saving. ). When engine output falls, exhaust gas temperature will also fall gradually, and when it becomes below the threshold value, even if it is forced regeneration, there is a possibility that it will not fully raise temperature (FIG. 7 state 2).

Therefore, if the exhaust gas temperature detected by the exhaust temperature detection device 37 is less than the threshold value, the temperature raising assist is started (steps S10-> S20-> S30-> S40). Controlled by the pump discharge pressure P2 and the pump discharge flow rate Q2, it becomes the engine output PS2 and exhaust gas temperature rises (FIG. 7 state 3).

When the exhaust gas temperature becomes higher than the threshold value by the temperature raising assist after the temperature assisting start, or when the automatic regeneration is completed by incineration of PM, the temperature raising assist is stopped (steps S40? S50? S60).

On the other hand, when the operation is resumed during regeneration, if the operator lowers the gate lock lever 5 to the first position A, the temperature raising assist is stopped (step S40? S50? S60) (Fig. 7 state 4).

In addition, even if the temperature raising / assist is stopped by the gate lock lever 5 lowering operation, automatic regeneration continues. When the operator lowers the gate lock lever 5 to the first position A and resumes operation, the engine output rises, the exhaust gas temperature becomes higher than or equal to the threshold value, and good regeneration is performed (FIG. 7 state). 5).

~ Effect ~

The effect of the exhaust gas purification system of the first embodiment will be described.

(a) The exhaust gas purification system according to the prior art has started the temperature raising assist based on the neutral positions of the operation levers 28 and 29. If the operating levers 28 and 29 are neutral, the engine output decreases. However, if the operation levers 28 and 29 are operated again to resume work, the engine output rises again, and the exhaust gas temperature may be lower than the threshold. Is low. In other words, if the time during which the engine output is lowered is short, there is no need to perform a temperature assist. On the other hand, unnecessarily raising the temperature may cause melting of the filter due to abnormal rise, which is also undesirable from the viewpoint of energy saving.

The exhaust gas purification system according to the present embodiment starts the temperature assist assist based on the operation position (second position B) of the gate lock lever 5. When the operator raises the gate lock lever 5 to the second position B, the operator is often spaced apart from the hydraulic excavator and rests, and the engine output time decreases. When the engine output decreases, the exhaust gas temperature also gradually decreases, and is likely to be below the threshold value. That is, the exhaust gas purification system according to the present embodiment starts the temperature assist assist only when necessary. Thereby, unnecessary temperature rising assist can be avoided.

(b) When engine output falls, exhaust gas temperature will fall gradually, but it will not fall immediately. If the exhaust gas temperature is equal to or higher than the threshold, no temperature assist is required. The exhaust gas purification system which concerns on this embodiment is equipped with the exhaust temperature detection apparatus 37, and does not assist in temperature rising, if the exhaust gas temperature detected by the exhaust temperature detection apparatus 37 is more than a threshold value. Thereby, unnecessary temperature rising assist can be avoided further.

(c) Exhaust gas purification system according to the prior art FIG. Exhaust gas purification system according to the present embodiment also controls the discharge pressure and the discharge flow rate of the hydraulic pump 11 to control the engine output PS1 (pump discharge pressure P1). • The temperature assist assist is started by increasing the engine output PS2 (pump discharge pressure P2 and pump discharge flow rate Q2) from the pump discharge flow rate Q1 to the engine output PS1 (pump discharge pressure P1). ) And pump discharge flow rate Q1] are common in that the temperature raising assist is stopped.

At this time, the discharge pressure of the pump 11 is adjusted by the switching control of the control valve 30, and the discharge flow volume of the pump 11 is adjusted by the tilting control of the regulator. After the control command is input, a response time occurs until the regulator of the control valve 30 or the pump 11 is operated. That is, even if the control command is made so as to be P2? P1, Q2? Q1, it does not immediately become P1, Q1, but the discharge pressure higher than P1 and the discharge flow rate higher than Q1 are maintained for a certain time.

The exhaust gas purification system according to the prior art commands the temperature assist assist stop based on the operation positions of the operation levers 28 and 29, and the operation lever 28 is controlled from the temperature assist assist stop command by the operation levers 28 and 29. 29) There is no time until the work resumes, and if the work resumes in this state, the operability may deteriorate.

The exhaust gas purification system according to the present embodiment commands the temperature assist assist stop based on the operation position (first position A) of the gate lock lever 5. The time from the temperature assist stop command by the gate lock lever 5 to the resumption of work by the operation levers 28 and 29, that is, the operator lowers the gate lock lever 5 to operate the hydraulic excavator. The time until the levers 28 and 29 are operated is longer than the response time of the regulator of the control valve 30 or the pump 11, and when the work is resumed, the engine output PS1 (pump discharge pressure P1 and pump) Discharge flow rate Q1]. Thereby, deterioration of operability at the time of resuming work can be prevented.

Modification example

While one embodiment of the present invention has been described above, the present invention is not limited thereto, and various modifications are possible within the spirit of the present invention. The modification is listed below.

1. In the operation of the present embodiment, explanation has been made on the premise of automatic regeneration control. However, the temperature raising assist may be performed during manual regeneration control. Manual regeneration control is started based on the command of the regeneration switch 38.

2. In the operation of this embodiment, automatic regeneration is started when the estimated PM accumulation amount by the differential pressure detecting device 36 reaches the accumulation limit value, and ends when the PM is burned out and the estimated PM accumulation amount is less than the accumulation allowance value. However, it may start after a predetermined time has elapsed and may end when a predetermined time has elapsed.

3. In the operation of the present embodiment, the PM accumulation amount and the differential pressure detection device 36 detect the differential pressure before and after the filter and calculate the calculation based on the detected value of the differential pressure. An air amount detecting device 51 for detecting the amount of air flowing into the engine and a boost pressure detecting device 52 for detecting the pressure of the air flowing into the engine are provided, and the air amount and air pressure of the air introduced into the engine by these sensors are measured. You may obtain | require by detecting and calculating based on this detection value. 8 is a diagram illustrating an entire configuration of an exhaust gas purification system of the work vehicle according to this modification.

4. In operation of this embodiment, in the functional block diagram (FIG. 4) of the controller 4, the regulator of the control valve 30 and the hydraulic pump 11 directly outputs the command signal which the controller 4 outputs. It receives and controls based on this command signal, but installs an electromagnetic valve, respectively, and the controller 4 transmits a command signal to these electromagnetic valves, These electromagnetic valves switch based on this command signal, and pilot hydraulic pressure The control pilot pressure may be generated using the hydraulic pressure of the circle 20 as the original pressure, and the regulator of the control valve 30 or the hydraulic pump 11 may be controlled based on the control pilot pressure.

<2nd embodiment>

In the first embodiment, one function of the regulator of the control valve 30 and the pump 11 and the vehicle body controller 41 for controlling them is to adjust the discharge pressure and the discharge flow rate of the hydraulic pump 11 to control the engine 1. Although the temperature raising assist means which applies a hydraulic load to) and assists the temperature rising at the time of regeneration, the temperature rising assist means is not limited to this.

Since the structure of 2nd Embodiment is the same as that of 1st Embodiment, it abbreviate | omits illustration. Details of the temperature assist assist start (S40) and the stop (S60) in the temperature assist assist control (see FIG. 5) of the vehicle body controller 41 are different.

The temperature rising assist start in step S40 is performed as follows, for example.

Normally, when the gate lock lever 5 is in the locked on state and no work is performed, the engine controller 43 adjusts the rotational speed of the engine 1 to the idle rotational speed N0 (low speed rotation) from the viewpoint of energy saving. (Auto idle control). At the time of regeneration, when the exhaust gas temperature is not sufficient, a temperature raising assist is performed.

The body controller 41 switches the target rotational speed of the engine 1 from the target rotational speed (child rotational speed N0) indicated by the engine control dial 2 to the predetermined rotational speed N1, and then the target rotational speed (rotational speed N1). ) Is transmitted to the engine controller 43 via the communication line 44. The engine controller 43 feedback-controls the fuel injection amount of the electronic governor 1a based on the target rotational speed (the rotational speed N1) and the actual rotational speed of the engine 1 detected by the rotational speed detection device 3, The engine 1 is controlled so that the rotational speed of the engine 1 becomes the first rotational speed N1. The rotation speed N1 is a rotation speed suitable for the regeneration control which can raise the temperature of the exhaust gas at that time to a temperature higher than the active temperature of the oxidation catalyst 33, and is, for example, a medium speed rotation speed of about 1800 rpm.

The temperature assist assist stop in step S60 is performed by controlling the rotation speed of the engine 1 to idle rotation speed N0 (low speed rotation speed). The load of the engine 1 decreases, and the exhaust gas temperature of the engine 1 falls.

Also in this embodiment comprised as mentioned above, the effect (a)-(c) of 1st Embodiment is acquired.

Third Embodiment

In the first embodiment, the work vehicle is a hydraulic excavator, and the gate lock lever 5 constitutes operation stop means for stopping operation by disabling the operation of the front work machine 102 of the hydraulic excavator, but operating the work vehicle. The stop means is not limited to this.

3rd Embodiment is demonstrated by FIG. 9 thru | or 12. FIG. This embodiment is a case where the present invention is applied to a wheel loader.

9 is a diagram illustrating an appearance of a wheel loader that is a work vehicle according to the present embodiment. In FIG. 9, the wheel loader 200 includes a body front part 201 and a body rear part 202 rotatably pinned to each other, and includes a body front part 201 and a body rear part 202. It consists of. The front work device 204 is installed in the vehicle body front part 201, the driver's seat 206 is installed in the vehicle body rear part 202, and the operation lever device 207, the steering wheel 208, and the like. The operation means is provided. In addition, the front wheel 235 and the rear wheel 236 are installed in the vehicle body front part 201 and the vehicle body rear part 202, respectively, and the engine body 1, the hydraulic pump 11, and the controller are installed in the vehicle body rear part 202, respectively. Each device, such as (4), is mounted. The front wheel 235 and the rear wheel 236 are connected to the output shaft of the engine 1 via a torque converter and transmission (not shown) to form a traveling system (not shown). When the accelerator pedal 61 (described later) is pressed, the rotation speed and the torque of the engine 1 increase, and the power is transmitted to the front wheel 235 and the rear wheel 236 through the torque converter and the transmission to travel. A steering cylinder 203 is provided between the body front part 201 and the body rear part 202, and the steering cylinder 203 is operated by operating the handle 208, and the body front with respect to the body rear part 202. The direction of the part 201 (the traveling direction of the vehicle body) is changed.

The wheel loader controls the rotational speed and torque of the engine 1 to output a command signal for controlling the traveling speed, including an accelerator pedal 61, a parking brake 62 as a parking braking means, and forward movement. A shift lever 63 is further provided which is selectively switched to the position F, the neutral position N, and the reverse position R. As shown in FIG.

10 is a diagram illustrating the functional blocks of the controller 4.

The command signal of the accelerator pedal 61 is input to the vehicle body controller 41 of the controller 4. The vehicle body controller 41 calculates the target rotational speed of the engine 1 based on the command signal, and transmits a control signal according to the result of the calculation to the engine controller 43 through the communication line 44, and the engine controller. 43 controls the electronic governor 1a based on the target rotation speed and the detection signal (actual rotation speed) of the rotation speed detection device 3, and controls the rotation speed and torque of the engine 1. The output shaft of the engine 1 is connected to the traveling system, and the traveling speed is controlled by controlling the rotation speed and the torque of the engine 1.

In the present embodiment, for example, based on the non-operational state of the accelerator pedal 61, when the temperature raising assist is started, a problem regarding unnecessary temperature raising assist occurs, and based on the operation state of the accelerator pedal 61. When the temperature assist assist is stopped, problems related to deterioration of operability at the time of restarting of the vehicle arise.

The parking brake operation position detection device 66 which detects the operation position is provided in the parking brake 62, and the detection signal of the parking brake operation position detection device 66 is also input to the vehicle body controller 41. FIG. The vehicle body controller 41 performs braking control of the wheel loader based on the command signal. When the parking brake 62 is operated to the braking position, the wheel loader is disabled to travel and stops its operation.

The shift lever 63 is provided with a shift lever operation position detection device 67 that detects the operation position, and the detection signal of the shift lever operation position detection device 67 is also input to the vehicle body controller 41. The vehicle body controller 41 performs switching control for switching to forward, neutral, and reverse based on the command signal. When the shift lever 63 is operated in the neutral position N, the wheel loader is disabled to travel and stops its operation.

The parking brake 62 and the shift lever 63 each constitute an operation stop means.

11 and 12 are flowcharts showing the processing contents of the temperature assist assist control of the vehicle body controller 41 according to the present embodiment. The difference from the flowchart shown in FIG. 5 is that the determination regarding the operation position of the parking brake 62 or the operation position of the shift lever 63 is performed in the processing of steps S20 and S50 shown in FIG. 5. Is the point.

That is, in FIG. 11, after determining that it is reproducing in step S10, it is determined whether the parking brake 62 was operated to the braking position based on the detection signal of the parking brake operation position detection device 66 (step S20). If it is determined that the parking brake 62 has been operated at the braking position, and the exhaust gas temperature is determined to be less than the threshold value in step S30, the temperature assist assist is started in step S40.

After the temperature assist start, if it is determined in step S50 that any one of the conditions 1, 2 (the parking brake 62 is in the braking position) and the condition 3 is no, the temperature assist is stopped in step S60.

In Fig. 12, after determining that playback is being performed in step S10, it is determined whether the shift lever 63 has been operated to the neutral position N based on the detection signal of the shift lever operating position detecting device 67 (step S20), when it determines with the shift lever 63 being operated to the neutral position N, and it determines in step S30 that exhaust gas temperature is less than a threshold value, a temperature raising assist is started in step S40.

After the temperature assist start, in step S50, if any of condition 1, condition 2 (the shift lever 63 is in the neutral position N), and condition 3 is determined to be no, the temperature assist is performed in step S60. Stop.

Also in this embodiment comprised as mentioned above, the effect similar to the effect (a)-(c) of 1st Embodiment is acquired.

(a) The exhaust gas purification system according to the present embodiment starts the temperature raising assist based on the braking position of the parking brake 62 or the neutral position N of the shift lever 63. When the operator operates the parking brake 62 to the braking position, or when the shift lever 63 is operated to the neutral position N, the wheel loader does not intend to travel and the engine output is deteriorated for a long time. Lose. When the engine output decreases, the exhaust gas temperature also gradually decreases, and is likely to be below the threshold value. That is, the exhaust gas purification system according to the present embodiment starts the temperature assist only when necessary. Thereby, unnecessary temperature rising assist can be avoided.

(b) When engine output falls, exhaust gas temperature will fall gradually, but it will not fall immediately. If the exhaust gas temperature is equal to or higher than the threshold, no temperature assist is required. The exhaust gas purification system which concerns on this embodiment is equipped with the exhaust temperature detection apparatus 37, and does not assist in temperature rising, if the exhaust gas temperature detected by the exhaust temperature detection apparatus 37 is more than a threshold value. Thereby, unnecessary temperature rising assist can also be avoided.

(c) The exhaust gas purification system according to the present embodiment commands the temperature assist assist stop based on the braking release position of the parking brake 62 or the forward position F or the reverse position R of the shift lever 63. will be. The time from the temperature assist stop command by the parking brake 62 or the shift lever 63 to the resumption of travel by the accelerator pedal 61, that is, the operator operates the parking brake 62 or the shift lever 63 to operate the wheel loader. Is allowed to run, and the time until the accelerator pedal 61 is operated is longer than the response time of the regulator of the control valve 30 or the pump 11, and the engine output PS1 (pump discharge pressure) (P1) and pump discharge flow rate Q1]. Thereby, deterioration of operability at the time of resuming running can be prevented.

1: diesel engine
1a: electronic governor
2: engine control dial
3: rotation speed detection device
4: controller
5: gate lock lever
11: hydraulic pump
12: pilot pump
13: hydraulic motor
14, 15: hydraulic cylinder
17 to 19: flow control valve
20: pilot hydraulic source
21: pilot relief valve
22: main relief valve
23: electromagnetic switching valve
24: pilot euro
25, 26, 27: remote controller valve
28, 29: operation lever
30: control valve
31: exhaust pipe
32: filter
33: oxidation catalyst
34: DPF device
35: position detection device
36: differential pressure detection device
37: exhaust temperature detection device
38: play switch
39: fuel injector for regeneration
41: bodywork controller
43: engine controller
44: communication line
51: air volume detection device
52: boost pressure detection device
61: accelerator pedal
62: parking brake
63: shift lever
66: parking brake operation position detection device
67: shift lever operating position detection device
100: lower traveling body
101: upper swing structure
102: front work machine
104a, 104b: travel motor
105: turning motor
106: engine room
107: Cab
108: driver's seat
111: boom
112: arm
113: bucket
114: Boom Cylinder
115: arm cylinder
116: bucket cylinder
200: wheel loader
201 body front
202 rear body
204: Front Work Device
206: driver's seat
207: Operation Lever Device
208: Handle
211: bucket
212 boom
213: Bucket Cylinder
214: Boom Cylinder

Claims (8)

With diesel engine,
A driven body driven by the power of the engine,
Operation means for instructing an operation of the driven member;
A working vehicle having operation stop means for stopping operation of the driven member,
A filter device disposed in an exhaust system of the engine and including a filter for collecting particulate matter contained in exhaust gas;
A regeneration device which incinerates and removes particulate matter deposited on the filter by raising the temperature of the exhaust gas;
In the exhaust gas purification system of a work vehicle provided with a regeneration control device for controlling the start and stop of the operation of the regeneration device,
Further comprising a temperature raising assist means for assisting the temperature rising of the reproducing apparatus,
The regeneration control device, during operation of the regeneration device, starts the operation of the temperature raising assist means when the operation stop means is operated to stop the operation of the driven member. . The exhaust gas detecting apparatus according to claim 1, further comprising an exhaust temperature detecting device for detecting a temperature of the exhaust gas,
In the regeneration control device, the operation stop means is operated so as to stop the operation of the driven member during the operation of the regeneration device, and when the exhaust temperature detection device detects a temperature below a threshold value, the operation of the temperature increasing assist means is performed. Initiating an exhaust gas purification system for a working vehicle. The exhaust gas purification system for a work vehicle according to claim 1, wherein the regeneration control device stops the operation of the temperature raising assist means when the operation stop means is operated to release the operation stop of the driven member. . The work vehicle of claim 1, wherein the working vehicle has a hydraulic pump driven by the engine.
And the temperature increasing assist means adjusts at least one of the discharge pressure and the discharge flow rate of the hydraulic pump to apply a hydraulic load to the engine. According to claim 1, The working vehicle is provided with an engine control device for controlling the engine,
And the temperature raising assist means instructs the engine control device so that the engine speed becomes a predetermined speed higher than the idle speed during the operation of the regeneration device. The method according to claim 1, wherein the operation stop means is a gate lock lever selectively operated at a first position enabling the operation of the driven member and a second position at which the operation of the driven member is disabled. Exhaust gas purification system of working vehicle. The exhaust gas purification system for a work vehicle according to claim 1, wherein the operation stop means is a parking brake that is operated to brake driving when the work vehicle is parked. The exhaust gas purifying system for a work vehicle according to claim 1, wherein the operation stop means is a shift lever selectively switched to a forward position, a neutral position, and a reverse position.

Images